This application claims the priority of German Patent Document 199 57 776.5, filed in Germany Dec. 1, 1999, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a functional component and method of making same. Preferred embodiments of the invention relate to functional components in the form of gate plates for automatic gear shift mechanisms with a locking gate, including engagement holes for engagement elements interacting kinetically with the functional component.
A functional component of the generic type is known from DE 196 41 706 C1 (corresponding U.S. Pat. No. 5,950,782), which describes an arrangement for locking a selection device, which is used for an automatically shifting gear shift mechanism, of a motor vehicle, the arrangement including a gate plate having two engagement holes. One engagement hole serves to receive a selection shaft, which forms an engagement element and, in that arrangement, is connected, securely in terms of movement for force transmission, to the gate plate, on the one hand, and to a manual selection lever, on the other hand. The second engagement hole serves as a gate slot of a locking gate, in which a projection of a lever arm of a differential lever used as locking actuator engages, thus forming a further engagement element. To enable the high forces to be transmitted without damage, the curved gate plate is, however, designed to be relatively thick and therefore heavy, with the result that the fine, filigree functional contours of the gate plate can only be produced precisely and reproducibly within a tight space in a very complex way. When the differential lever is actuated, its projection, which is guided in the slot, strikes against the gate slot walls, depending on the direction of actuation, which on the one hand causes disruptive impact noises and on the other hand, on account of the hard impact, causes wear to the projection and the walls of the slot.
An object of the invention is to refine a functional component of the generic type, in particular a cam plate of an automatic gear shift mechanism with locking gate, in such a manner that it can be used to transmit high mechanical forces while being easier to produce and impact noises during interaction with engagement elements guided in the holes are as far as possible avoided. A further object is to provide a method for producing the functional component with reduced outlay.
This object is achieved according to preferred embodiments of the invention by providing a plate-like in the form of a gate plate of an automatic gear shift mechanism with locking gate, having engagement holes for engagement elements which kinetically interact with the functional component, wherein the functional component comprises, in sandwich form, at least three stamped parts, which bear flat against one another, are unreleasably connected to one another and each have at least two engagement holes for engagement elements which kinetically interact with the functional component, the engagement holes in the stamped parts being arranged congruently with respect to one another, at least one of these holes, in a middle stamped part, having a hole wall which is provided with an elastomeric plastic cover.
This object is also achieved according to embodiments of the invention by providing a method of making such a functional component, including:                stamping three smaller individual metal sheets out of a larger metal sheet, each individual metal sheet having at least two engagement holes for engagement elements which kinetically interact with the functional component,        placing the individual metal sheets against one another in a sandwich structure with corresponding engagement holes in each of the individual stamped metal sheets congruent with one another,        providing a hole wall of at least one of the engagement holes in the middle stamped part with an elastomeric plastic cover, before the individual sheets are placed against one another, and        non-detachably connecting the three individual metal sheets together after they have been placed against one another.        
The sandwich structure of the invention allows precisely reproducible production of precision functional contours of the functional component with relatively little outlay, whereas the rigidity for the transmission of high forces remains ensured. This is assisted by the provision of a plurality of relatively thin-walled individual parts for the component, which can be machined considerably more easily compared to the known single, thick-walled component. In this case, it is advantageous to use the stamping process, which is readily manageable and can also be used to produce the individual parts themselves at considerably lower outlay compared to the single-piece component. The elastomeric plastic cover for at least the hole wall of one of the two engagement holes provides a substantially soft and therefore noiseless resilient abutment for the engagement element, so that there are no disruptive impact noises which cause wear. Overall, the use of stamped parts which can be produced with little outlay and are easy to connect to form a functional component, as well as the noise damping which can be achieved with the simple means of an elastomeric plastic cover results in a production process for the functional component which is easy to execute yet constitutes a reliable process.
Expedient configurations of the invention are described below and in the claims.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.